<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
	<style type="text/css">
		.box{
			width: 200px;
			height: 200px;
			background-color: red;


			transition:all 1s;
/*			过度        所有属性    1s   需要一秒*/


		}



/*		鼠标移入到  类名box  标签上时  才会执行  css 样式*/
		/*.box:hover{
			background-color: orange;
			font-weight: bold;
		}*/

		.box:active{
			background-color: blue;
			border-radius: 50%;
			width: 300px;
			transition: all 1s;
		}


	</style>
</head>
<body>


<div class="box">
	
111

</div>




</body>
</html>